num = 18;
num1 = 20;

if num>num1:
    print("num比num1大")
elif num<num1:
    print("num比num1小")
else:
    print("num和num1相等")


# **************if嵌套**************

num2 = 5
num3 = 4
num4 = 10
num5 = 15
if num2>num3:
    print("num2比num3大")
    if num4>num5:
        print("num4比num5大")
    else:
        print("num4不比num5大")
else:
    print("num2不比num3大")